Production of blown asphalts in the presence of a phosphorous containing catalyst



PRODUCTION OF BLOWN ASPHALTS IN THE PRESENCE OF A PHOSPHOROUS CONTAINING CATALYST Joseph W. Van Wyk, Chicago, 111., assignur to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application February 8, 1954 Serial No. 409,008

13 Claims. (Cl. 208-5) The present invention relates to an improved method of oxidizing certain high boiling hydrocarbon fractions to produce ductile, homogeneous asphalts of high solubility in carbon tetrachloride and low temperature susceptibility. In particular, the invention relates to an improved catalytic oxidation process, employing phosphorus compounds, e. g. P as catalysts for the transformation of high boiling petroleum residuums and the like to asphaltic products. v

The production of so-called blown asphalts by the air oxidation of various residual oils derived from petroleum is a well-known technique. Such blown asphalts are generally preferred for such purposes as coating irrigation canals, waterproofing conduits, roofing, etc. Many techniques have been proposed for the air oxidation of petroleum residuums and one of the better processes embodies the uses of a phosphorus catalyst such as P 0 A process of this type is described and claimed inU. S. Patent No. 2,450,756 to Hoiberg. In that pat ent, a petroleum residuum is heated to a temperature in .the range. of fiom about 200 to about 350 F. and a small portion of that residuum is separately mixed with P 0 to form a catalyst slurry. The slurry is then introduced to the main body of the residuum and the total mix is heated to a temperature in the range of from about 400 to about 550 F. while vigorously agitating and introducing large quantities of air. 'Asphaltsproduced by this blowing technique have, generally speaking, excellent properties; but it has been found that certain requirements laid down by purchasers of such materials cannot be met consistently when applying this technique to. the diverse types of residual oils which are available at refineries in different parts of the country. It has been found, however, that certain modifications in the process of the aforementioned patent result in unexpected improvements in the properties of blown' asphalts so prepared, almost without regard to the source of high boiling hydrocarbon charge stock.

In accordance with the present invention, a suitable heavy petroleum fraction, of the type hereinafter described in detail, is heated to a temperature of at least 400 F. and preferably from about 460 to about 500 F. While this oil, e. g. a residuum, is being heated to' such temperature, a relatively smaller amount of-, for example, the" same residual phosphorus-containing catalyst at a temperature highenough to. assure a fluid, readily oil, is' admixed with a stable" perature; to attainment oftemperature of '60- pumpable slurry. Theffi hour after that temperature catalyst slurry thus produced is rendered smoothand homogeneous by vigorous agitation at: such temperature. The time required for such homogenization will vary, of course, depending upon quantities of oil, type of. oil, method of agitation, etc, but for most purposes from about 10 minutes'to about minutes and preferably at least about 20 minutes of mixing are adequate; the same time that the slurry'preparation is begun or somewhat prior thereto, the main bulk of the residual oil t he t J;

to be oxidized is raised to oxidation temperature, i. e.

about 460 F. and contacted with substantial quantities .the catalyst W k suitable spray nozzle over as 2,859,167 Patented Nov. 4, 19 58 "ice . of air. This thermal oxidation is carried out, in accordance with the present invention, for a period of 'at least one-half hour and preferably from about 2 to 4 hours before the catalyst slurry is introduced. -Such thermal oxidation is generally continued until an increase in softening point of the residuum occurs equal to at least about 10 F. and preferably somewhat higher. Thus,

for example, beginning the oxidation with a residuum having a softening point of F., the thermal oxidationis continued until at least a softening point 'of and preferably from about to about F., is attained. Subsequent to such an increase in softening point, the catalyst slurry may be introduced into the residual oil rapidly, i. e. five minutes or less. The introduction of the catalyst slurry may, however, take susbtantially longer if desired. Thus, it may be carried out over a period of an hour or even longer. It has not been found necessary to so operate, however, andfrom a practical standpoint, it is desirable to complete the'catalyst introduction in as short a period of time as possible.

One of the most difficult requirements to meet in the specifications of many blown asphalt purchasers is that the asphalt should have a solubility in carbon tetrachloride of at least 97%. Prior to the discovery of the present oxidation process,fit has been very difiicult toiconsistently produce asphalts having a high solubility. As a result of the present process, however, solubilities in ex cess of 99% are readily and consistently obtainable and from a variety of base oils. A typical specification for blown asphalt is that of the U. S. Bureau ofReclama-- tion for Catalytically Blown Asphalt Cement for- Buried Asphalt Canal Lining (ASTM D42). The requirement of at least 97% solubility in CCL, is a part thereof.

Whereas, P 0 is the preferred phosphorus-containing catalyst for use in accordance herewith, it should be understood that other stable phosphorus-containing ma terials may be used, c. g. red phosphorus or the stable sulfides of phosphorus, such as phosphorus pentasulfide, phosphorus'sesquisulfide, phosphorus sulfide, etc.

it has been found that unless each of the above features of the present process are carefully adhered to, the consistent production of a high grade blown asphalt cannot be attained. Thus, for example, it is essential main body of residual oil be brought to oxidation temperature before any catalyst is introduced thereto, and it is also essential that at least about /2 hour of thermal oxidation of the stock take place before catalyst addi:

tion occurs. As indicated above, the preferred oxidation temperature is about 460 F. and unless the main body of the oil is at essentially this temperature during the so-called thermal oxidation period, the advantages inherent in this novel pro-cess are not fully realized. Thus, whereas the introduction of air during, the preliminary stage may begin before the temperature is raised to about 460 'F., the full effectiveness of the airrtreatment is not realized until the oil is substantially at the higher tem:

' In' any event, if air introduction is begun prior about 460 F., it is necessary that. air introduction continue for at least a halfhas been reached.

: In accordance with the preferred method of introducing slurry, the same is spread by means of a much a surface of the residual oil as possible so that rapid and complete contact of catalystiand oil can be obtained substantially at once throughout a large volume of the oil, While not absolutely essential, it is highly desirable and in accordance with the preferred method of operation that the catalyst slurry be heated to atemperature between about 250 and 350 F. duringthe formation and preparation thereof. A rather high introduction temperature of this order that thel -5 is indicated in any event because of the need for a fluid readily flowable slurry. This feature, while important,

can be varied to some extent without unduly affecting the results of the process. The critical features of having the oil atoxidation temperature prior to catalyst addition and preliminary thermaloxidation for a period of at least one-half; hour, cannot be varied beyond the rather narrow limits stated; Y e 'The customary residual oil employed in the production ofblown a sphalts for use in the present process is a crude :oil residue derived from an asphaltic or semi-asphaltic base'stock. Some so-called pa'raflinic base stocks of the non asphaltic base class may be blown with air in accordance with the present invention to produce highly useful asphalts, however. It is, preferred to employ heavy hydrocarbon fractions derived from such petroleums as those occurring in the U; 8. Gulf Coast field, the so-called Mid-Continent crude residual oil and various other asphaltic petroleums; Consistent production of satisfactory blown a sphalts has heretofore residual oils derived from certain sour crudes of the type retinal-n Wyoming. However, such oils have been readily oxidized to useful asphalts in accordance herewith. In addition to those residual oils commercially employed as asphalt base materials, lubricating oil distillates and solventexams resulting from the treatment of various petroleumrfractions with such selected solvents as phenol, nitrobenzene, .B,Bfdichloroethylether Chlorex), S et cg eitheraloneorin combination with other high molecular weight petroleum fractions such as the residual oils or, lubricating distillates, may be oxidized in accordance here'with toproduce asphaltic products suitable for a wide range of uses. And whereas the present invention is particularly adapted to the production of waterproofing as-v phalts and the like, it should be. apparent that a wide range of stocks may be handled to produce a variety of asphalt products. V

For purposes of illustrating the oxidationof a typical Wyoming sour crude residual oil to produce an excellent cana1 lining asphalt, the following example is set forthf EXAMPLE the oil was vigorously agitated. The initial-air'introduc tion was continuedfor about 3 /2 hours at the end of which time the softening point of the material in the tank hadrisen to 84 F. Duringthe preliminary thermal b en. u o a n b e rom.

Softening point 7 oxidation of the main body in the oil, about 4 tons of the same stock Was charged to a steam jacketed slurry tank" equipped with a mixing impeller, gear pump, and cir-' culating lines and the same was heated to a temperature of about 325 F. After such temperature was attained, powdered P 0 in an amount sufiicient to give an ultimate catalyst concentrationin the main charge of, about 1.2% was then vigorously admixed with the oil. Due to the small size of the steam jacketed slurry tank, inwas necessary to prepare two separate slurry charges, in the first of which the catalyst comprises 20% by weight and in the second about 15% by weight. These slurries were then introduced tothe main body of the oil in a period of about one hour (much lesstime would have been required if a single batch of slurry were available), all the I while continuing the introduction of air at the rate of about 20,000 cubic feet an hour. of the slurry and the overall mixture was continuedduring slurry addition. The inspections of the, final product. wereas follows: V Y

Softening point, F Penetration at'77 F Ductility at 77'F Solubility in CC1 percent in Table 1 are set forth data'demonstrating the effect of failing to observe the critical features of the present process. Thus is shown the, effect of' failing tojhavej the j main body of the residuum heatedto oxidation tempera,- turepriorto the introduction of the catalyst slurry. On q the other hand, data are provided which; demonstrate; the disadvantage of adding the catalyst slurry to the 'resi- I duurnwhich although heated to the oxidation temperature, had not been previously air-blown for at least about 4 a half hour. The interdependence ;of the requirements; that the residual oil'be brought tooxidation temperature; before any catalyst addition occurs and that suchoilbe blown for a substantial period of" time prior to'addingj the catalyst, while not entirely understood, is apparent; It is obvious from the datagin Table 1 that they are,mu-., tually dependent and that unless each of these requirements are'observed, the consistent production of satis: j

factory blown asphalt has been difiicult ifnot impossible to attain. And, whereas, the solubility of'carbontetra-f chloride is particularly susceptible to change whenthese; important factors are disregarded; .this-is not the only; characteristic which fails to pass specification and other physical properties'h ave been shown tobe inferior when 1 the present process is not employed; .In addition Jit has Table 1 Run Number 1 2 3"- 4;

Viscosity at180 F. (SSF) 220 220 102 102, i Percent P205 in Total Batch 1. 15 1. 15 1 1 1. 5 Percent P105 in' Slurry 20 2 20' 20 6' Slurry Temperature, degrees. 300-350 300-350.: 350 350 j I, 7 Duration of Thermal OXid.'( 7 60. 1 0 305 i Air Rate (cc./min./gram) ca. 2. 5 ca. 2. 5- 1 1s I Still Temp. During Slurry Addition, de 460 4601 500 500 l Oxidation Temperature, degrees '460 460 H 500 500. '460 460 Total, Length of Oxid.'(Thermal and Catalytic) (Min- J i utes) 325 365; 1, 300. 1, 250 V 420. 420-41 Inspections of Final Product: V r

Softening Point, F 183' I86 182. 193 184, 178: Penetration at 77 F- 54 "50 V '58 71 641, 627 Ductility at 77 Fm-- 3. 5 3.7 2. 9 Y 3.0 3. 851 Solubility inv C014, percen 99. 9 9. 78 95. 2 98.11 89. 1 9231' e 1 Slurryadded rapidlyi.-e. 1 minute, V 1 f 2 Ainwasturned on a short: time before slurry was introduced lengthoi time r t f Mechanical agitation V comparative purposes a typical specification, viz. that'of the U. S. Bureau of Reclamation, is set forthbelow:

Softening point, F 175-200 Penetration at 77 F 5060 Penetration at 32 F NLT 30 Penetration at 115 F NMT 120 Ductility at 77 F NLT 3.5 Solubility in CCL; NLT 97 The amount of catalyst employed in the oxidation of heavy oils to blown asphalts in accordance herewith should generally fall within the range of from about 0.1 to about 5.0 and preferablyfrom about .75 to about 1.5% by weight of the totalhydrocarbon charge. The slurry which is preferably formed from a portion of the main body of the residuum oxidized generally should comprise about to about 25% catalyst and preferably from about to about In any event, the slurry should have suflicient oil to permit adequate dispersion of the catalyst therein .and yet not have too great an amount so as to dilute the catalyst to less than about a 10% concentration. a r

Air is introduced rapidly and in large quantities to the main body of the charge during both the preliminary thermal oxidation as well as during the catalytic oxidation to both oxidize and agitate the same. Rates of air introduction of from about 6.to.about'70 cubic feet of air per minute per ton and higher may be employed but it is generally found that an amount of air from about 6 to cubic feet of air per minute per ton of charge gives excellent results in plant practice. The introduction of the oxidizing gas is continued until the desired softening point is obtained, i. e. at least about 175.

The product may, if desired, be blown with steam toward the end of the air blow to remove any objectionable odors from the oil. Since steaming has a slight adverse eflfect on the penetration-softening point relationship, it should be started before the product of desired softening point is obtained.

Percentages given herein and in the appended claims are by weight based upon the total hydrocarbon oil charge, unless otherwise specified.

In the appended claims, the phrase high molecular weight petroleum hydrocarbons is employed to designate the residual oils or base stocks which may be oxidized to a blown asphalt in accordance herewith. In connection with the use of such term, it will, of course, be understood that the heaviest of petroleum hydrocarbons are not high molecular weight in the sense that many polymers are high molecular weight, but with the possible exception of a paraffin wax, essentially any heavy petroleum oil or residuum of the type defined hereinabove may be employed.

The phrase hydrocarbon slurry oil is employed in the appended claims to designate the oil used in the catalyst slurry and may, as indicated above in accordance with the preferred embodiment of the present invention, comprise the same oil as that being oxidized. On the other hand, it may comprise a different petroleum oil. Thus, it has been found that particular advantage may be gained by employing a somewhat lower boiling stock than that being oxidized in those instances wherein a very heavy residuum is being blown so as to permit easy handling of the catalyst slurry at somewhat lower temperatures. in particular, it has been found that lubricating oil extracts such as phenol extracts or Chlorex extracts may be used to excellent advantage. Other petroleum fractions such as lubricating oil base stocks, etc. may likewise be used. Synthetic polymers, e. g. high molecular weight butylene polymers, etc. may likewise be used.

In those instances where a portion of the oil being blown is used as slurry oil and particularly when blowing a heavy residuum, it has been found especially desirable,

although not essential, to use a portion of the thermally oxidized material for this purpose. Thus, the portion used as slurry oil is not separated from the main body until after a substantial period of thermal oxidation has taken place. It has been found that the resulting slurry may be more readily homogenized and is of much smoother appearance. Because the blowing does increase blown asphalt when a more fluid, lower-boiling slurry oil is employed. It should be understood, however, thatwhereas the terminology employed in the appended claims might indicate that the hydrocarbon slurry oil and the high molecular weight-hydrocarbon? are difie rent oils, such is not necessarily the case.

, Having thus described our invention, what I- claim asnovel and desire to protect by Letters Patent, is as follows:

1. The method of catalytically oxidizing suitable high molecular weight hydrocarbons to produce blown asphalts, which method comprises contacting said high molecular weight petroleum hydrocarbonswith substantial quantities of air at a temperature in the range of.

from about 400to about 500 F. for a period of at least about one-half hour, subsequently introducing a fluid homogeneous slurry of a phosphorus-containing cat'- alyst selected from the group consisting of phosphorus pentoxide, stable phosphorus sulfides and red phosphorus in a hydrocarbon slurry oil to said high molecular weight petroleum hydrocarbons while at such a temperature, the amount of said phosphorus-containing catalyst being from about 0.1 to about 5.0% based upon the total weight of high molecular weight petroleum hydrocarbons and hydrocarbon slurry oil present, and continuing the introduction of air to the resulting admixture of catalyst,

hydrocarbon slurry oil and high molecular weight petroleum hydrocarbons.

2. The method of claim 1 wherein the phosphoruscontaining catalyst is phosphorus pentoxide.

3. The method of claim 1 wherein the hydrocarbon slurry oil employed to slurry phosphorus-containing catalyst is a portion of the high molecular weight petroleum hydrocarbons which had been separated from the main body of such hydrocarbons and admixed with the phos- Y phorus-containing catalyst.

4. The method of claim 1 wherein the phosphorus containing catalyst is phosphorus pentoxide and the hydrocarbon slurry oil employed to slurry the phosphorus catalyst is a portion of the high molecular weight petro-' leum hydrocarbons which had been separated from the main body of such hydrocarbons and admixed with the phosphorus-containing catalyst.

5. The method of claim 1 wherein the hydrocarbon slurry oil employed to slurry phosphorus-containing catalyst is an extract resulting from the solvent extraction of a lubricating oil base stock. a

6. The method of claim 1 wherein the phosphorus- 7 containing catalyst is phosphorus pentoxide and the hydrocarbon slurry oil is an extract resulting from the solvent extraction of a lubricating oil base stock.

7. The method of catalytically oxidizing suitable high molecular weight hydrocarbons to produce blown asphalts, which method comprises contacting said high molecular weight petroleum hydrocarbons with substantial quantities of air at a temperature in the range of from about 400 to about 500 F. for a period of about 2 to about 4 hours, subsequently introducinga fluid homogeneons slurry of a phosphorus-containing catalyst selected fnomiflte groupzconsistingofiphosphorus pentoxide, stable,

phosphorus sulfides andred phosphorus in a hydrocar- L1. to. abontl5.Q%; based upon-the total weight of, high molecular weight petroleum: hydrocarbons and hydrocarbon slurry oil present,;and continuing the; introduction of air. to the: resultingnarlmixture of catalyst, hydrocarbjon slunryi oil? and high molecular weight petroleum hydrocarbons.

8; The. method. offclaim-7 wherein the phosphoruscontaining vcatalyst: i's phosphorus pentoxide.

9.. The method, ofpclaim. 7 wherein the hydrocarbon slurry: Qi-lfimployedto. slurryphosphorus-containing catalyst is-a portion of, the high molecular Weight petroleum hydrocarhonswhich had, been; separated. from the main bo y of 81110115 hydrocarbonsiandi admixed with the phos phorns:containingicatalyst. r 7

1,02, The method of claim: 7 wherein the: phosphoruscontainingrcatalyst is phosphorus ,pentoxide and the hydrocarbon slurry oil employed: to slurry thecph'osphorus catalyst: is a portion, of the high molecular weight petroleumhydrocarhonswhich had been separated from the main body of suchhydrocarbons and admixed with the phosphorus-containingcatalyst;

11., The; method. oi claim; 7- Whereimthe hydrocarbon slurry oil; employed tcn slurry; phosphorus-containingacatd V alyst is an extract resulting from the solvent extraction ofa lubricating oil base stock. i

12... The method of claim 7 wherein the phosphorus'e containing catalyst is" phosphorus pentoxide and" the lay-,- drocarhon' slurry oil* is an extract resulting from, the

solvent extraction of a; lubricating "oil base st'ock.- 7 13. The method of claim 7 wherein the hydrocarbon slurry oil employed to slurry the. phosphorus-containing 7 catalyst is a portion of'the molecular: weight pe-i troleurn hydrocarbons: which .had been separated from: themain body of such hydrocarbonsafter saidmain body. 1 of hydrocarbons hadbeen'subject ed to a-substantial-:period:'

of thermal oxidation;

RefierencesiCitedi-im thefile ofthis patent Um 1 ED STATES' PATENTSV' Edson Apr. 27,.1954

Thurston; Apr. 7 13, 193 .7; 7 i 

1. THE METHOD OF CATALYST OXIDIZING SUITABLE HIGH MOLECULAR WEIGHT HYDROCARBONS TO PRODUCE BLOWN ASPHALTS, WHICH METHOD COMPRISES CONTACTING SAID HIGH MOLECULAR WEIGHT PETROLEUM HYDROCARBONS WITH SUBSTANTIAL QUANTITIES OF AIR AT A TEMPERATURE IN THE RANGE OF FROM ABOUT 400* TO ABOUT 500*F. FOR A PERIOD OF AT LEAST ABOUT ONE-HALF HOUR,SUBSEQUENTLY INTRODUCING A FLUID HOMOGENEOUS SLURRY OF A PHOSPHORUS-CONTAINING CATALYST SELECTED FROM THE GROUP CONSISTING OF PHOSPHORUS PENTOXIDE, STABLE PHOSPHORUS SULFIDES AND RED PHOSPHORUS IN A HYDROCARBON SLURRY OIL TO SAID HIGH MOLECULAR WEIGHT PETROLEUM HYDROCARBONS WHILE AT SUCH A TEMPERATURE, THE AMOUNT OF SAID PHOSPHORUS-CONTAINING CATALYST BEING FROM ABOUT 0.1 TO ABOUT 5.0% BASED UPON THE TOTAL WEIGHT OF HIGH MOLECULAR WEIGHT PETROLEUM HYDROCARBONS AND HYDROCARBON SLURRY OIL PRESENT, AND CONTINUING THE INTRODUCTION OF AIR TO THE RESULTING ADMIXTURE OF CATALYST, HYDROCARBON SLURRY OIL AND HIGH MOLECULAR WEIGHT PETROLEUM HYDROCARBONS. 